Gastroenteritis

Gastroenteritis can be caused by a number of different germs including:

• viruses (for example norovirus, rotavirus, hepatitis A)
• bacteria (for example Salmonella, Campylobacter, Shigella)
• parasites (for example Giardia, Cryptosporidium).

Gastroenteritis can also be caused by toxins that some bacteria produce in food (for example Staphylococcus aureus,Clostridium perfringens).

The germs that cause gastroenteritis can be found in food, water, soil, animals (including pet, farm and wild animals) and in humans.

You get gastroenteritis by taking in germs or their toxins through your mouth. This can be by:

• drinking or eating something contaminated with germs or toxins
• contact with microscopic amounts of faeces (poo) or vomit from an ill person. This may occur directly by close personal contact, or indirectly by touching contaminated surfaces such as taps, toilet flush buttons, toys or nappies. The germs then pass from your hands to your mouth
• handling pets and other animals.

When people get gastroenteritis they often assume that the last meal they ate gave them food poisoning, but often it will be from another meal sometime within the last few days, or from contact with an infected person.

The time it takes for symptoms to start depends on the germ or toxin you have been infected with.

Gastroenteritis symptoms usually begin 1 to 2 days after you have taken in the germ, but it can be as early as 1 hour (for example staphylococcal toxin) and as long as 60 days (for example Listeria infection).

Symptoms can include:

• nausea and/or vomiting
• diarrhoea, sometimes containing blood
• stomach pain/cramps
• fever
• generally feeling unwell, including tiredness and body aches.

If you have diarrhoea and/or vomiting there is a good chance you have gastroenteritis.

There are many causes of gastroenteritis, and laboratory testing of a faecal specimen is necessary to confirm what germ is causing your gastroenteritis.

Treatment depends on the germ causing the gastroenteritis, but in general people with gastroenteritis should:

• In the event of diarrhoea, fluid replacement is the first priority. Drink plenty of fluids such as plain water or oral rehydration drinks (available from pharmacies) to avoid dehydration. Dehydration is especially dangerous for babies and the elderly.
• Dehydrations from loss of fluids can be dangerous at any age, but particularly so in babies and young children who can dehydrate very quickly. Remember to increase fluid intake during episodes of diarrhoea. Oral rehydration solutions (ORS) replace salt and sugar from the body. It is important to follow the instructions on the packet and mix the solution correctly.
• Breastfeeding mothers should continue to breastfeed as normal but should supplement breast milk with ORS using a cup and spoon.
• Avoid anti-vomiting or anti-diarrhoeal medications unless these are prescribed or recommended by a doctor. Do not give anti-diarrhoeal medications to children.
• See a doctor if diarrhoea and/or vomiting are severe or persistent.

If you experience severe or prolonged symptoms you should visit a doctor.

While you have the infection

• Do not go to work or school for at least 24 hours after symptoms have finished, or 48 hours if you work in or attend a high risk setting, such as health care, residential care or child care, or handle food as part of your job.
• Wash and dry your hands thoroughly after going to the toilet.
• Avoid preparing or handling food for other people until symptoms have resolved. If you must prepare or handle food, thoroughly wash your hands beforehand to reduce the risk of spreading the infection to others.
• Immediately remove and wash any clothes or bedding contaminated with vomit or diarrhoea using detergent and hot water.
• After an episode of diarrhoea or vomiting, clean contaminated surfaces (for example benches, floors and toilets) immediately using detergent and hot water. Then disinfect surfaces using a bleach-based product diluted according to the manufacturer’s instructions.
• Clean carpet or soft furnishings contaminated with diarrhoea or vomit immediately using detergent and hot water and then steam clean.
• Avoid contact with people who have gastroenteritis symptoms.
• Wash and dry your hands thoroughly after changing nappies, going to the toilet, cleaning up vomit or diarrhoea, or handling animals, and before eating or drinking. If hand-washing facilities are not available use an alcohol-based gel.
• Raw foods such as meats, poultry and eggs can contain bacteria that cause gastroenteritis. Keep raw foods separate from cooked and ready-to-eat foods (for example salads) to prevent cross-contamination. Store raw meat below ready-to-eat food in the refrigerator and use separate chopping boards and knives for raw and ready-to-eat foods.
• Cook foods thoroughly to a temperature of 75 °C or until meat juices run clear and are not pink.
• Keep cold food below 5 °C and hot food above 60 °C.

The following precautions against gastrointestinal infections are important in areas of poor hygiene.

These precautions are particularly important when travelling to developing countries especially in Asia, the Pacific islands, Africa, the Middle East and Central and South America.

• Always wash your hands with soap and water after using the toilet and before preparing or eating food.
• Avoid eating or drinking:
  • salads
  • raw or cold seafood including shellfish
  • raw or runny eggs
  • cold meat
  • unpasteurised milk and dairy products
  • ice in drinks
  • ice-cream
  • flavoured ice blocks.

  Fruit that you peel yourself is usually safe. Remember – ‘cook it, boil it, peel it, or leave it’.

• Use bottled water or disinfect water (by boiling, chemical treatment or purifiers) for drinking and brushing teeth. To ensure water is safe to drink it must be kept at boiling point for at least 1 minute (or for at least 3 minutes at altitudes over 2,000 metres) before drinking. If this is not possible, then iodine tablets or water purifiers should be used – follow the instructions carefully.
• Drinks that are usually safe from contamination include tea and coffee made with freshly boiled water, commercially canned or bottled water or carbonated drinks, beer and wine. Ensure that seals on bottles are unbroken and avoid ice in your drinks. Drink directly from the can or bottle rather than use a potentially contaminated glass or other drink container.

Read more about travel health.

Is there a vaccine for gastroenteritis?

There are currently no vaccines that protect against most causes of gastroenteritis in Australia.

Rotavirus vaccine is suitable only for babies under 6 months of age. It is included in the Western Australian Immunisation Schedule (external site) and is free.

However, typhoid, cholera and hepatitis A vaccines are available for travellers to high risk areas overseas and can provide some protection. See your doctor or travel medicine specialist at least 2 months prior to departure to see if any vaccinations or medications are recommended.